1. Field of the Invention
This invention relates to a tensioner for use in a transmission gear using a transmission strap such as V belt, timing belt, flat belt, wire rope or the like.
2. Description of the Prior Art
For example, as a tensioner for automotive vehicle, there is known one which, as shown in FIGS. 1 and 2 of the accompanying drawings, has a rotatable outer member 1a formed by a race member 11a having an inner track and a pulley member 12a fitted to the race member and bearing against a belt 8a and, an inner member 2a formed by a track member 22a having an outer track and a holding member 23a holding the track member, the inner member 2a is fixed to a base 9a, and a plurality of rolling members 3a are disposed between the outer member 1a and the inner member 2a. In such a tensioner, the base 9a is supported for oscillation about a pin 10a fixed to a support member 7a at a position different from the axis of the inner member 2a, and the base 9a is fixed to the support member 7a by means of a fixing bolt 4a in a position wherein the force of a tension spring 6a having one end fixed to the restraining portion 91a of the base 9a and the other end fixed to the support member 7a is balanced with a component of the force of the tension of the belt 8a bearing against the pulley member 2a, whereby a proper tension may be imparted to the belt 8a.
However, mounting such a conventional tensioner requires spaces for the base 9a, the pin 10a, the tension spring 6a, etc. and in addition, if the arrangement of said parts is not proper, a proper tension cannot be imparted to the belt. Therefore, in the case of an automotive vehicle which requires various mechanisms to be compactly arranged in a limited space, such tensioner has encountered a number of difficulties in the design and assembly of the arrangement.